Hydrodynamically and chemically induced in situ kaolin particle release from porous media an experimental study

Contaminant transport in the subsurface is decidedly influenced by the presence of colloids that are clay type particles, like kaolinite. To understand the contaminant associated colloid transport, one needs to know how release of these colloidal particles in in situ condition is affected by change in geochemical condition. In this work an attempt has been made to experimentally study the effect of different parameters like flowrate, void fraction, ionic strength, and pH on release of kaolin particle from the porous bed of kaolin–sand mixture. It was observed that there exists a critical velocity at 0.017 cm/s for the release of kaolin, and plugging of these released particles was significant in the bed. This plugging was explained by size exclusion and agglomeration of particles. It was also observed that with increase of pH and decrease of ionic strength kaolin release increases.